Multi-way tumbler switch



April 16, 1957 H. w. TREVASKIS 2,739,165

MULTI-WAY TUMBLER SWITCH Filed NOV. 9, 1954 United States Patent OMULTI-WAY TUMBLER SWITCH Application November 9, 1954, No. 467,840

1 Claim. (Cl. 200-6) This invention relates to tumbler switches for thecom trol of electrical apparatus and circuits, and more particularly tomulti-way tumbler switches for the selective control of electricalapparatus for actuating aircraft aileron and elevator trimming tabs.

Four-way tumbler switches for the control of aircraft trimming tabs areknown, and are usually mounted on the aircraftcontrol stick and areselectively operated by the pilot to energize one of four electricalcircuits which control the electric motors and screwjacks of an elevatoror aileron trimming tab, whereby the trim of the aircraft may be readilyadjusted.

The object of the present invention is to provide a novel type ofmulti-way tumbler switch.

According to the invention a multi-way electric tumbler switch comprisesa housing, a plurality of pairs of electrical contacts within saidhousing, said contacts being arranged on a common pitch circle and eachpair of contacts being adapted to be connected across a source ofpotential, a tumbler pivotable to bridge any one of said pairs ofcontacts and resilient means selectively operable to pivot said tumbler.

Preferably the tumbler comprises a rectangular block of non-conductivematerial of square cross section, one end of which abuts the base of thehousing. A bearing member having a conical recess in the centre thereofextends axially from the other end whereby side thrust on said recesscauses the block to move angularly about one of the edges of that endwhich abuts the base of the housing.

At the end adjacent the bearing member, metal facings are secured toeach of the faces of the tumbler which lie adjacent each pair ofcontacts, whereby angular move ment of the tumbler will cause one of thefacings to engage with one pair of contacts to complete an electricalcircuit.

Preferably also the means for moving the tumbler comprise an operatingmember having a conical projection extending axially from one endthereof to engage the conical recess of the bearing member of thetumbler. A

spring guide extends axially from the base of the conical projection,and the member is held in position by means of a helical springsurrounding said spring guide, said spring being compressed between theclosed end of an operating thimble and a flange extending outwardly fromsaid spring guide. Movement of the operating thimble in one directionwill therefore cause the tumbler to move in the opposite direction.

Alternatively the operating thimble may be of square cross-section andassociated with recesses in the housing to guide the movement of saidthimble.

The invention will now be described with reference to the accompanyingdrawings of which,

Figure 1 is a sectional view of a multiway tumbler switch constructedaccording to the invention.

Figure 2 is a view of the tumbler switch illustrated in Figure 1 takenon the line A-A, looking in the direction of the arrows.

According to one embodiment of the invention (Figures 1 and 2), ahousing 1 to be connected to an aircraft control stick is steppedintermediate its ends, and a plug of insulating material 2 seals the endof the larger diameter portion of the housing 1 remote from the step 3.Four pairs of electrical contacts 4, 4 extend axially from the insulatedplug 2 into the housing, being substantially equidistantly spaced on acommon pitch circle.

The plug of insulating material 2 is formed in the centre thereof with asquare recess 5 having outwardly tapering sides, each side beingparallel to one pair of contacts. A further recess 6 of smaller area, isformed symmetrical with and in the base of the recess 5 whereby a step 7is formed, the smaller recess 6 having sides which extend substantiallyparallel with the axis of the housing. A rectangular tumbler 8 ofnon-conductive material and square cross-section is located on the step7, said tumbler 8 being provided with a projecting portion 9 offrusto-conical form the smaller diameter of which is remote from therectangular portion, said frustoconical portion 9 fitting into thesmaller recess 6.

A bearing member 10 extends axially from the other end of the tumbler 8having a conical recess 11 in the centre thereof, and metal facings 12are secured to each of those faces of the tumbler which are adjacent apair of contacts. The facings 12 extend only part way along the axiallength of each face of the tumbler from the end adjacent the bearingmember.

A collar 13 having an outwardly extending flange 14 at one end islocated within the smaller diameter portion of the housing, beingsecured therein by means of the flange 14 which abuts the step 3 of thehousing, and which is held against the said step 3 by means of aninsulating washer 15 which abuts the adjacent end of the pairs ofcontacts 4, 4 on the side thereof remote from the said flange 14. Theother end of the collar 13 is inwardly turned to form an annular recess16 between the inner periphery of the collar and the inwardly turnedportion.

An operating thimble 17 is formed of hollow frustoconical cross sectionbeing closed at the smaller diameter end, and having an outwardly-turnedportion formed at the larger diameter end thereby forming an annularrecess 18 between the outer periphery of the thimble and theoutwardly-turned portion.

The inwardly turned portion of the collar and the outwardly turnedportion of the thimble are associated mutually to limit the axialmovement of the thimble 17 in one direction, and also to provide afulcrum about which said thimble may pivot.

An operating member 19 comprising a spring guide 20, an outwardlyextending flange 21 and a conical projection 22 is located interior ofsaid operating thimble, the conical projection 22 engaging in theconical recess 11 of the bearing member 10. A helical spring 23 iscompressed between the closed end of the operating thimble and theoutwardly extending flange 21 and a cover 24 of resilient materialsecured to the operating thimble encloses the open end of the housing toprevent the ingress of moisture, dirt and the like.

Each pair of contacts are connected to positive and negative sources ofpotential in a known manner, the positive contacts of each diametricallyopposed pair being connected together.

The switch is operated by pivoting the operating thimble 17 in any oneof four directions. This movement, acting through the helical spring 23,moves the conical projection 22 in the direction opposite to that of theoperating thimble 17. The conical projection thus moves the bearingmember 10 causing the tumbler 8 to rock about one edge of its baselocated in the recess 3 formed Patented Apr. 16, 1957- 3 in, the base ofthe housing. Thus pivotal movement of the thimble in one direction willpivot the tumbler in a diametrically opposite direction.

This movement forces one of the facings 12 of the tumbler to bridgetheassociated pair of contacts and complete the circuit to the desiredaileron or elevator trimming tab control mechanism.

Having-now described my invention what I claim is:

A snap-action, multi-way electric switch comprising a housing having arectangular recess in the base thereof, and an inwardly-turned annularlip at the other end, a plurality of pairsof electrical contacts withinsaid housing said contacts being disposed on a common pitch circle, andeachpair of contacts being adapted to be connected across a source ofpotential, 2. tumbler having a rectangular base pivotable on any one ofthe edges of said rectangular recess to bridge any one of said pairs ofcontacts, anoperating rod, in pivotable engagement with 4 said tumbler,a frusto-conical member outwardly lipped to engage behind theinwardly-turned lip on the housing, and a spring fitted in compressionbetween said operating rod and said frusto-conical member, wherebyangular movement of the frusto-conical member in any of four directionspivots t-he tumbler in the opposite direction to bridge a pair ofcontacts.

References. Cited in the, file of this patent UNITED STATES PATENTS1,426,193 Holmgren Aug. 15,, 1922' 2,589,025 Phelps et a1. 11, 19522,706,753 McGowan Apr. 19, 1955 2,739,193 Mason Mar. 20,1956

FOREIGN PATENTS 440,662 Germany Feb. 11, 1927 626,139 Great Britain July11, 1949

